The studies supported by this grant are designed to increase our understanding of the nature, physiology and metabolism of renal antigens, either structural or planted, that can be involved in nephritogenic immune reactions. Levels of circulating antigens reactive with anti-glomerular basement membrane antibodies are quantitated using radioimmunoassay techniques. Manipulations which may affect the levels and/or excretion of these antigens are studied. Assessment of variations in nephritogenic antigens between tissue strains and species are measured. Studies to determine the nature of other glomerular capillary wall and tubular antigens distinct from the clasic basement membrane antigens that can be involved in nephritogenic immune reactions are also being studied utilizing similar technology. Lastly, the role of foreign materials which can become trapped or planted within the kidney for subsequent nephritogenic immune reaction is being evaluated.